The Prairie Rain Garden is a student installation project currently under construction at the University of Washington Botanic Gardens along Wahkiakum Lane. The currently unfunded, low-resource student project aims to make the UW Campus more sustainable by turning an underutilized and problematic site into a functional native plant garden. Previously, the site was covered with non-native weeds and excess stormwater runoff from an adjacent parking area frequently ponded on the gravel trail. After heavy rainfall, a portion of the trail would often need to be re-routed due to muddy and unsafe conditions. The unmanaged runoff created a trail hazard during winter months when puddles on the trail freeze and turn to ice. Goals of the installation include mitigating urban flooding, improving runoff water quality and demonstrating sustainable stormwater management.
Funding for the garden from CSF will allow the project to meet its goals by providing materials to increase functionality. Funds will also reduce maintenance needs, increasing the resiliency of the installation by creating a larger denser native planting, increasing infiltration and reducing erosion, which will create a better end product.
The Prairie Rain Garden offers measurable impacts on biodiversity and water quality. The garden aims to reduce negative impacts of stormwater by conveying and infiltrating the runoff through a series of planted depressions. Previously, the site had little topographical diversity and was covered with non-native grasses and weeds. The project will convert the site into a structurally and biologically diverse wet prairie habitat. Mounds and depressions mimic the varied topography of western Washington prairies while infiltrating and conveying runoff. Establishing this “microtopography” also increases soil moisture gradients, supporting a diverse plant palette.
The garden is currently planted with six plant species including native perennial grasses and forbs. Malcolm Howard, project leader, has seeds from an additional eighteen native species that will be added to the site in Spring 2015. The native vegetation utilized in the project provide numerous benefits over the non-native vegetation previously established on the site. Native grasses have deep roots that are able to uptake large amounts of water and stabilize the soil. Bunch grasses filter out sediments while maintaining growing space for native forbs. Further, these species create habitat for wildlife including native pollinators, aquatic insects and amphibians.
The garden has multiple positive impacts on water resources. It reduces stormwater quantity via soil infiltration and evapotranspiration. Additionally, the garden can improve water quality via sediment capture, pollution degradation and nutrient uptake. Pollutant reduction will be achieved through the use of plants and soil microbial communities, which can degrade pollutants (e.g. motor oil) contained in runoff. Plants used in the installation can also uptake excess nutrients contained in runoff from fertilizers used in adjacent ornamental gardens.
Student Leadership & Involvement
The Prairie Rain Garden was planned and designed by graduate student Malcolm Howard as part of the Master of Environmental Horticulture program. Malcolm had two student volunteers help him install the project over the summer of 2014 and has received other student support for the project in the form of donated plant materials. Malcolm is working with Sustainable Stormwater Coordinator Matthew Schwartz, who has provided consultation support for the project and is currently discussing a potential collaboration with the Society for Ecological Restoration UW Chapter for long term maintenance of the site. Once the installation is completed, a written report will be created. The written report will include an as-built report and stewardship plan. The project will be presented to students and faculty in Spring of 2015.
Education Outreach and Behavior Change
The Prairie Rain Garden aims to be a publicly visible and accessible example of a low-resource green infrastructure project. Located at the entrance to the Union Bay Natural Area, the project offers many opportunities to influence and inform both students and the public. The project is in a high pedestrian traffic area, which provides multiple outreach and education opportunities. While working on the site, Malcolm has had dozens of informal conversations about the purpose and progress of the rain garden with students, staff, faculty and UBNA users. These informal interactions have allowed for numerous opportunities to engage the public on topics related to native plants, stormwater management and ecological restoration. Malcolm presented the rain garden to an Intro to Restoration Ecology class in October 2014, in which he explained the problem being solved, goals and scope of the project. Additionally, he is in contact with an undergraduate student who is interested in assisting with planting the rain garden in spring of 2015.
Feasibility, Accountability & Sustainability
Malcolm formally proposed and presented the project to UWBG Director Sarah Reichard, Assistant Director Fred Hoyt and Manager of Horticulture David Zuckerman, and the project was approved in June 2014. Malcolm has been receiving guidance from David Zuckerman, along with faculty advisors Professor Kern Ewing and Jim Fridley. Up until this point, Malcolm has installed the project using volunteers, salvaged plants and personal funds.
Resources requested using funds from the CSF small project grant include drain rock and plants. The drain rock will reduce erosion and sedimentation of the garden and overflow trench, while improving drainage. Adding established plants will allow the rain garden to uptake more water, reduce sedimentation, create more biodiversity and will enable the site to better outcompete weeds. These resources will create a more sustainable and permanent installation that requires less maintenance and will increase likelihood of project success, maximizing overall project sustainability.
Item Source Cost/Item Quantity Delivery Tax (10% Default) Total Cost
plants: plugs Sound Native Plants $1.50 72 $10.80 $118.80
plants: 4" pots Sound Native Plants $2.65 10 $2.65 $29.15
plants: 1 gallon pots Sound Native Plants $6.00 10 $6.00 $66.00
drain rock Pacific Top Soils $40.85 2 (yards) $85.00 $16.67 $183.37
Install plants: January - March 2015
Spread drain rock: March 2015
Write report: March - May 2015
Present project: May 2015